After dental sealant was polymerized (cured) with LTV irradiation, the material was found to contain low molecular weight impurities. The ethanol-soluble unpolymerized fraction wasanalyzed by GC/MS (electron ionization) and ESI-MS and found not to contain the expected contaminant bisphenol-A, but to have plasticizers and fatty acid esters as welt as other unreacted and partially reacted starting materials.